We view a lot of videotapes here at Videomaker. We get hundreds of entries for our annual contest, we review instructional videotapes in every issue, we even accept Tools & Tips and Video Q&A submissions on tape. Some of the videos we receive are top-notch. Some are not so good.
Especially in the area of sound recording, it’s easy to spot the same problems cropping up again and again. It’s a fact of human nature that we all tend to make the same mistakes; for videomakers, it’s part of learning the craft. But good videomakers, like you, learn from the mistakes of others.
What follows is a list of the 10 most common audio recording mistakes, in no partiular order.
Each problem has an explanation and a solution or two.
Apply the solutions to your own video productions. They will never sound the same.
Over-reliance on the built-in mike.
While your camcorder’s microphone is almost always the most convenient way to record audio, it’s rarely the best. For one thing, a built-in mike is usually too far from the sound source. This makes your audio boomy and indistinct, with little clarity or crispness. The right distance between lens and subject is not usually the best distance for picking up audio.
For another, few camcorder manufacturers invest more than a couple of dollars in their built-in mikes. Condenser mike elements are extremely cheap; this is one area where manufacturers cut costs. Built-in mikes often sound tinny, with limited frequency response and relatively high noise levels.
Solution: Use an external microphone whenever possible. Even an inexpensive mike ($50 or so) will provide higher quality audio than the built-in version. You can also position an external mike much closer to the subject. Put a stick mike on a stand, hide it in a plant, or attach a lavalier to your talent. You’ll get crisp, intelligible audio from an external mike nine times out of 10.
Not using headphones. You wouldn’t dream of focusing on your subject, composing a shot, and recording a scene without looking in the viewfinder. Why should you be any less concerned about your audio?
Headphones are your aural “viewfinder.” They tell you what’s being recorded, good or bad. Many of the gremlins in this list of audio mistakes can be heard and ferreted out only with headphones.
The other option, which is really no option at all, is to discover your audio problems after you shoot. Then it’s too late.
Solution: Use headphones. Though not as often as in the past, most camcorders still come with a built-in headphone jack.
Use a pair of inexpensive, sealed, over-the-ear headphones; train yourself to hear all the intrusive little sounds that our ears have learned to ignore. Small non-sealing phones are better than nothing, but the open-ear design lets in a lot of external sound. It can be hard to distinguish between that and what’s going to tape. If you’re going to play it smart and use headphones, use the real thing.
Recording unwanted background noise. It’s amazing how things that go unheard during recording become almost deafening on playback. The cxcitement of shooting doesn’t often allow for critical listening.
It’s also part of our aural makeup to tune out repetitive or consistent sounds after just a few minutes. In time, our brain stops hearing the low hum of an air conditioner or appliance, the babble of a radio, even the roar of rush-hour traffic. Microphones, on the other hand, do no such thing. If a sound was bouncing around the locale, your viewers will hear it.
Solution: Learn to listen like a mike. In other words, be merciless. When you walk into a new recording environment, close your eyes and listen to the “silence” of that room. Try and pick out every sound, and weigh its potential to infect your soundtrack. If you can, eliminate the sound. If you can’t get rid of it, try a different mike, new mike placement or a different room entirely. As with solution #2, always consult your headphones.
Always recording with AGC. Auto gain control (AGC) may be a marvel of modern electronics, but it’s not the best for some audio sources. AGC tries to make every sound the same level, regardless of what it is. When your on-screen talent pauses, for example, auto gain begins to crank up the record level until he or she speaks again. Every little sound, from a rustling audience member to a sniffling cameraperson, comes through loud and clear. When the speaker resumes, the noise disappears again.
Auto gain masks the nuances of a musical performance, and turns dramatic stage productions into alternating periods of dialogue and stage noise. It even amplifies camcorder handling noises, if you’re using the built-in mike.
Solution: Set record levels manually. If your camcorder has manual controls, you’ll get better results without AGC.
Your camcorder will record what it should during quiet moments-silence. You can record anything without relying on AGC if you learn to predict sound level changes and set your record levels conservatively.
Try to think of a time when you heard the breathing, pumping effects of ACG on a television special or major motion picture. You probably can’t, because the pros rarely use ACG.
Letting wind ravage your soundtrack. Mikes respond to changes in air pressure-it’s their job. Thus, if air moves past an unprotected mike, the mike picks it up and makes ugly sounds. Most built-in camcorder mikes have foam wrapped around the actual element, but this is rarely enough protection for even moderate winds.
Some camcorders attempt to reduce buffeting wind noise electronically, by killing the low-frequency response of the mike. This is no solution-the filter takes too much desirable sound with it. The human voice gets thin, music sounds tinny, and wind noise is still audible.
Solution: Get a real windscreen, or switch microphones. Professional soundmen use large, fuzzy wind socks that completely encase the mike. With these, they can record their talent in a full-fledged gale.
Similar products exist for camcorders, though foam is the more common material. If these don’t suffice, use an external microphone. By design, it maybe less susceptible to wind noise. At the very least, you’ll be able to wrap an external mike in a professional-style wind sock. You may even want to make one yourself. You can whip wind noise.
Using the wrong external mike. There’s more to using external mikes than just plugging one in. Mikes come in a wide variety of pickup patterns, element designs and physical shapes. Certain mikes are better than others for a given application. Using the wrong external mike may result in sound worse than that of your camcorder’s mike.
If you’re in a highly reverberant space, for example, choosing an omnidirectional mike will guarantee that you pick up every stray echo. If you camcorder’s mike is directional, and you can record from close to your subject, you’ll get better sound from the built-in mike.
Solution: Learn all you can about microphones. The better you understand microphone types, the better your sound will be. The basics of mike design are easy to understand; learning them will forever change the way you record audio. With time and experience you’ll know exactly when to use a given mike, where to place it, and how it will sound. Pros choose their mikes from experience-good sound recordists know their mikes like an artist knows her brushes.
Picking up hum, buzz and electronic noise. We live in a world of electronic devices, each with its own aura of electromagnetic radiation. Some gizmos are no problem; others crank out a strong enough field to infect your audio. Plug in an external or wireless mike, and you’ve just added an antenna to your camcorder.
Electronic interference can take on a variety of unpleasant forms. You may hear a constant abrasive buzz, a high-pitched whine, even the muted babble of voices from a nearby radio station. Mixed in with your audio, these sounds can trashcan a whole day of shooting.
Solution: Locate and eliminate these sounds before you shoot. Run your cables, get everything set and powered up, and listen with headphones. Unplug or power down devices until you locate the source of unwanted sounds. Hear a whine? Look for an electric motor or compressor. Buzz or hum? Look for a grounding problem. Keep audio cables from running parallel with extension cords; you can reduce buzz by letting them cross one another at right angles. In time you’ll learn to recognize and track down the telltale sounds of our electronic jungle.
Recording with mismatched levels. Many people think that every electrical signal has the same strength-all you need to do is plug one component into another, and you’ll get good sound. Not true.
A line-level signal from a professional tape deck, for example, is one million times stronger than a microphone signal. Needless to say, you can’t plug a tape deck into a mike input without first reducing the signal. Yet videomakers frequently record with mismatched levels.
When you try to combine line-level and mike-level signals, the result is either a weak signal bathed in noise, or massive distortion. Individual components work best with a somewhat narrow range of signal strengths. If you have to run an input-level control at either extreme, you’re probably working with the wrong signal level.
Solution: Properly match signal levels at evey component. Learn the difference between mike and line levels, and know which components use each. Buy the necessary adaptors and attenuators to interconnect every piece of your audio setup. If you plan to plug a tape deck into your camcorder’s mike input, plug an attenuator in line. To step a mike level signal up to line level, use a transformer. Give each link in your audio chain the signal level it expects for optimum performance.
Once you have the proper signal level, you can set your record level controls where they need to be: near the middle of their range. Even if you don’t have manual record levels, AGC funcdons better if given the right signal.
Adapter and connector abuse. I’ve seen videomakers shoot with a 12-inch stack of adaptors and attenuators protruding from their camcorder’s mike input jack. Not only is this un sightly and easily unplugged, it’s extremely hard on the input jack. No jack should support much weight; if asked to for long, it will break.
Every connection also increases your chances of failure. Connections oxidize and lose their ability to pass signal, and tend to come apart easier as they age. If a mike connection works itself loose during a once-in-a-lifetime shot, you’ll never forgive yourself.
Solution: Use the fewest possible connections. If this means buying one specific adaptor to eliminate three others, do it. If you’re handy with a soldering iron, make your own special cables. For the sake of your mike input jack, run a short mini-jack cable between your adapters and input jack. Carry the weight of the adapters on the tripod or camcorder body itself. Use Velcro or gaffer’s tape to hold them in place.
Not paying enough attention to audio. I’ve saved the most devastating audio mistake for last. It also happens to be the easiest to correct.
The vast majority of videomakers virtually ignore the audio portion of their videos, even though we all know how important good audio is. It pulls the viewer in. It sells the most outrageous visual effects. It cuts straight through to the viewer’s emotions.
Most audio problems are simple to solve, if the videomaker invests just a little effort. Videos often suffer from sound problems that take about five minutes, and less than $10, to solve. That’s a cheap fix, for the sake of your video.
Solution: Care about your audio. Spend a few extra minutes making sure the aural portion of your videos has the same impact as the visual portion. Familiarize yourself with the other nine solutions on this list, and apply them to your videos.
Become a student of sound as well as video. Listen to big-budget productions-try to figure out what makes their audio programs so powerful. Read books.
And, most important, pay attention to your audio.
Loren Alidrin is Videomaker‘s technical editor.